Stereoscopic image capture involves recording two images of the same scene from slightly different perspectives. One technique to accomplish this is to use two cameras, physically offset from one another, to record the scene. Another technique is to use two lenses on a single camera that are physically offset from one another, and record two separate images on a large film or imaging sensor.
Likewise, stereoscopic projection can utilize two projectors to present left and right eye images at a single screen. The projectors are physically offset from one another and the projector lenses are shifted with respect to the spatial light modulator (or panel) to overlay the images on a single screen. Alternatively, a single projector with a large panel may be utilized with two projection lenses, which are offset from one another. Typically, a relay lens and splitting prisms are inserted between the panel and projection lenses to allow space for shifting the projection lenses such that the images overlay.
Known catadioptric systems (i.e., mirror and lens systems) can capture stereo images with a single camera detector and a single lens. See, e.g., J. Gluckman & S. Nayar, Rectified Catadioptric Stereo Sensors, IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 24, No. 2, February 2002, herein incorporated by reference. For rectified imagery at the sensor over a common field of view, Gluckman and Nayar show a compact stereoscopic capture system with three mirrors and a single camera. Left and right eye images are considered rectified if their epipolar lines are aligned with the rows or columns of the sensor array. The resulting field of view (FOV) of the camera is halved in the direction of the plane containing the normals of the mirrors.
FIG. 1 is a schematic diagram of a known stereoscopic image capture system 100, which is presented in the Gluckman & Nayar reference introduced above. A single camera and capture lens 110 is with this type of stereoscopic image capture system, as explained above. Planar mirrors labeled “M1”, “M2” and “M3” are included in the stereoscopic image capture system 100 illustrated in FIG. 1. If the camera sensor has pixel rows or columns that are parallel to the plane containing the normals of the mirrors, then the two images at the sensor are rectified. As illustrated, “FOV” describes the original angular field of view of the camera (in the plane of the paper). “FOV/2” depicts the common field of view of the two optical paths, which unfortunately is only half the size of the original field of view (FOV). What is needed in the art is a technique for reclaiming the full FOV of the original camera lens, thus overcoming the deficiencies of the above-mentioned conventional approach.